Bidirectional communication with sCB-function

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grifcj replied on 12 Mar 2009 2:19 AM

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If you're using an AP, as you say, your ED code only needs two function calls to establish a link to the AP:

SMPL_Init(sCB);

which registers your callback function and issues a join request to the AP. Once your ED is joined with AP, you can attempt to link with the AP to set up a communication channel with it using the returned link ID.

SMPL_Link(&tAPLinkID);

You'll notice that in SMPL_Link(), you pass a link ID variable by reference. If your ED successfully links to the access point, the function will set the link ID to a valid value (most likely the integer 1). This will be the link ID that you use to communicate with the AP via the functions SMPL_Send and SMPL_Receive. You may think of the link ID as an identifier for the logical connection between the AP and ED.

It is important that the AP is listening for a link request when the ED attempts to link. After receiving a join request, your example code probably goes into an infinite loop making SMPL_LinkListen calls until it hears the link request from the ED. Upon hearing a link request, the AP will send a link reply to the ED, and the SMPL_Link function will give you a valid link ID for communicating with the AP.

If you haven't already, you may want to peruse the documentation that installs with TI's SimpliciTI installer swrc099b. Mine installed at C:\Texas Instruments\SimpliciTI-1.0.6\Documents. Here you should be able to find an SimpliciTI API reference, SimpliciTI's detailed specification, and a few other useful documents.

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driesione replied on 12 Mar 2009 6:02 AM

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Hi Grifcj,

thanks for replying! It contains good information but most of the things i already knew.
I already did a lot of reading in the simpliciTI-documents. But i'am still doubting about my linkID's.

I will show you what i have.
For the ED i use the two function that you said. They look like this:

linkID_t linkID1;

while (SMPL_NO_JOIN == SMPL_Init(sCB))
  {
    ...
  }

while (SMPL_SUCCESS != SMPL_Link(&linkID1))
  {
    ....
  }

SMPL_SUCCESS == SMPL_Send(linkID1, msg2, sizeof(msg2))

if (sPeerFrameSem)
    {
      uint8_t     msg[MAX_APP_PAYLOAD], len;

      // process all frames waiting
        if (SMPL_Receive(linkID1, msg, &len) == SMPL_SUCCESS)
        {
          ioctlRadioSiginfo_t sigInfo;
          sigInfo.lid = linkID1;
          SMPL_Ioctl(IOCTL_OBJ_RADIO, IOCTL_ACT_RADIO_SIGINFO, (void *)&sigInfo);
          buf = ~buf; // toggle commando
          BSP_TOGGLE_LED2();
          BSP_ENTER_CRITICAL_SECTION(intState);
          sPeerFrameSem--;
          BSP_EXIT_CRITICAL_SECTION(intState);
        }
    }

static uint8_t sCB(linkID_t linkid)
{
    if(linkid == linkID1)
    {
        sPeerFrameSem++;

    }
}

Now, i wonder if my "linkdID's" are correct filled in, in every function?
The sCB-function is just to set the semafoor. This semafoor is checked in the main-function
(the if-statement that i copied)
Sending to the AP with "linkID1" already works. Receive-function asks for the same linkID so i would think that i implemented every linkid owkey but i'am still not sure?

Kind Regards

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grifcj replied on 12 Mar 2009 2:44 PM

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driesione:

while (SMPL_NO_JOIN == SMPL_Init(sCB))
  {
    ...
  }

I might suggest looping until SMPL_SUCCESS rather than just checking for SMPL_NO_JOIN. SMPL_Init can fail for a number of reasons, and I don't think you'd want to let the code pass unless it was successful.

driesione:

SMPL_SUCCESS == SMPL_Send(linkID1, msg2, sizeof(msg2))

I'll assume this is meant to be in an if-statement. Your useage of the link ID looks correct to me.

driesione:

          ioctlRadioSiginfo_t sigInfo;
          sigInfo.lid = linkID1;
          SMPL_Ioctl(IOCTL_OBJ_RADIO, IOCTL_ACT_RADIO_SIGINFO, (void *)&sigInfo);

I've never used this particular function or object, but it looks quite correct. Doesn't it work?

driesione:

static uint8_t sCB(linkID_t linkid)
{
    if(linkid == linkID1)
    {
        sPeerFrameSem++;

    }
}

Again, this seems right. The linkid variable in the callback function will be set to whatever link ID the incoming message is associated with. Since you only have one link ID, i.e. linkID1, this is the one you check for.

You didn't mention any problems, so I assume everything is working correctly? Certainly, if you were misusing your link IDs, you wouldn't be able to reliably communicate between the AP and ED.

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driesione replied on 13 Mar 2009 7:33 AM

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Hey Grifcj,

thanks for replying! Your tip about the SMPL_SUCCES except SMPL_NO_JOIN was a good one.

For the rest it effectively works. I was just afraid and wanted to be sure. I didn't test anything yet.

Kind Regards